Coronal transient geometry. I - The flare-associated event of 1981 March 25

Abstract

The Mar. 25, 1981 large white light coronal transient associated with an optical 2B flare and X 2.2 X-ray event, although one of the first described in the lower corona, is typical of flare-associated coronal transients seen at higher altitudes. Postevent observations indicate that the material injected into the field of view above the occulting disk left the instrument's field of view, and the preexisting coronal material was also depleted. A detailed comparison of inferred radial and azimuthal distributions of the polarized brightness, modeled by a simple three-dimensional figure whose symmetry axis is perpendicular to the limb, are compared with observed quantities. The model is found to be able to reproduce the major features of the transient.